System for the rectification and amplification of signals of relatively high frequency



June 10, 1941.

J. G. TOVAR 2,244,741 SYSTEM FOR THE RECTIFICATION AND AMPLIFICATION OFSIGNALS OF RELATIVELY HIGH FREQUENCY Filed May 23, 1940 2 Sheets-Sheet 1f/ if i: @TAE/ f y www www@ l fz *75 2% k/7 V5 June l0, 1941. J. G.TOVAR 2,244,741l

SYSTEM FOR THE REQTIFICATION AND AMPLIFICATION 0F smNALs oF RELATIVELYHIGH FREQUENCY Filed May 23, 1940 l -2HSheets-Sheet 2 Z\ I HW v wwwPatented June 10, 1941 SYSTEM FOR. THE RECTIFICATION AND AMPLIFIUATION0F SIGNALS OF RELA- TIVELY HIGH 'FREQUENCY Jorge Guzman Tovar, MexicoCity, Mexico Application May 123, 1940, Serial No. 336,846 In MexicoMarch 3'1, 1937 116 Claims.

The present invention relates to a system for the rectification `andamplification of `signals of relatively high frequency, and moreparticularly to the rectification Iand amplification of alternatingcurrents, such as used in radio-telephonie and radio-telegraphicsignals.

One of the objects of the `present invention is the provision of a novelamplifying circuit embodying a novel rectifying lagent capable ofpassing a current of larger intensity than any heretofore known.

Another object of the present invention is the combination of a novelrectifier or detector and an interrupting means capable of impressingthe rectified lsign-al on a Ktransformer or other suitable amplier forfurther amplification.

A third object of the invention is the combination of a novel rectifiercapable of passing sufficient 4current to energize a relay.

A fourth object of the invention is a novel amplifying circuit embodyingla novel rectifier capable of passing a current of sufiicient intensityto energize a relay from the radio frequency currents as received in anordinary receiver.

A fifth object of the present invention is the provision of a novelradio circuit or circuits especially capable of utilizing the novelrectifier according to the present invention.

yOther objects of the present invention will appear from the moredetailed description in the specification and drawings and the claimsappended hereunto.

Referring to the drawings:

Figure 1 isa simplified radio circuit illustrating the form of fthepresent inventiton utilizing the novel rectifier and a relay for theamplification of the rectified signals.

Fig. 2 is similar to Fig. 1, but illustrates a form of relay used ingreater detail.

Fig. y3 is 'a Idiagrammatic illustration of the novel rectifier anddetector of lthe present invention;

Fig. 4 is a plan view of the relay diagrammatically shown in Fig. 2;

Fig. 5 is a section taken along the line 5-5 of Fig. 4;

Fig. 6 is a section taken along *the line 6 5 of Fig. 4;

Fig. 7 is a detail section taken along the line 'I-"I of lFig. 4;

Fig. 8 isa diagrammatic illustration of a modified form of amplifier.

Referring to Figure 1, the usual antenna I,

which may be of any of the well known types,

such as the single strand antenna, or others well known in the art, is'shown connected yto ground at 2 through the usual primary radiofrequency lco-il 3. Wound on the same core with the primary coil 3 isthe secondary radio frequency coil 4, which is tuned by the variablecondenser 5 connected in parallelltherewith 'and to ground at 6. -Theseelements comprise the usual tuned radio `frequency circuit and may besubstituted by any of the `tuned circuitswell known ein the art.

A novel rectifier or detector 1, which is composed 'of a selenium-leadmaterial, to be described hereinafter in detail, is shown connected inseries circuit with the radio frequency coil 4 and 8 so that radiofrequency currents induced in the coil 4 will pass through the detector'I and coil lIl which is wound about the permanently magnetized ironc-ore indicated at 9, and thus comprises the actuating coil of ya relay,the armature o-f which is indicated at 10.

The relay armature I 0 is adapted to close a circuit withcontacts II andI2 as actuated by the currents in coil 8.

Connected in series with the contacts I I and I2 is the primary coil ofa transformer indicated in general at I3, and having an intermediatecenter tap at I4, so that a portion of said primary coil will be inseries with battery I5 and variable resistance I6 =through contact I2and 'armature I ll, and another portion of' said primary will be inseries with battery I5 and Variable resistance I6 in series throughcontact I I, although it may be noted here that the circuit establishedthrough these portions of the primary coil I3 will cause the current toflow in each portion in a direction opposite to the current fioW in thelother portion. Mounted on the same iron core I1 VWith the primarytransformer coil I3 is the usual secondary I 8, and this in turn isconnected in circuit with the usual voice co-il I9 of the magneticspeaker, indicated in general at 20.

The operation of the modification described in Figure 1 is as follows:The modulated radio frequency current received at antenna I, induces aresponse in the secondary radio frequency coil 4, which `is tuned so asto be in resonance with the -oarticular frequency being received in theusual manner by the variable condenser v5. yI'his radio frequencycurrent being received is prevented from passing through coil "8 in itsoriginal state by the rectifier 1, which only permits the passage of apulsating D. C. current, corresponding 1n general to the modulations ofthe modulated radio frequency current.

In other words, the current passing through the coil 8 is a demodulatedcurrent similar to that actuating the earphones of any ordinary crystalset, except that due to the novel type of rectier and detector hereinused, this current is of very much larger intensity than any heretoforeknown in the art, being of the order of about 1 to 2' milliamperes andto l5 volts. In other Words by the use of the present novel detector itbecomes possible to rectify from the current ordinarily received at theantenna of a radio set, a current of sufcient intensity to operate arelay.

The current passing through coil 3 which corresponds to the modulation,or in other words, the audio frequencies impressed upon the radiofrequency carrier at the transmitting station correspondingly moves thearmature I ii, which as before stated, is acted upon by the energizedcoil 8.

The armature Ii) will, therefore, close a circuit alternately throughcontacts II and I2, when the armature touches Contact II, it establishesa circuit through battery VI5 and variable resistance I6, so as to senda current through one section of the primary coil I3, this current beingmuch greater in intensity than the pulsating current which as beforestated, energizes the relay through coil 8. It may be noted that thevoltage and intensity of the first mentioned current is determinedentirely by the electrical characteristics of the battery I5, and thatany suitable source of D. C. current may be used instead of the batteryI 5.

The armature I also closes periodically the circuit through contact I2,sending current through another -portion of the primary coil I3 in adirection that is opposite to the direction of the current throughcontact II, and thus portions of the primary I3 have established thereina pulsating current which corresponds to the original audio frequenciesat the transmitting station. A corresponding A. C. current is, ofcourse, induced in the secondary I8 and in the Voice coil I9 in theusual manner, so as to produce the corresponding sounds in the magneticspeaker 2U.

Referring to the embodiment of the invention specifically disclosed inFig. 2, there is here shown a similar Atuned circuit including` theantenna I, coils 3 Vand 4, ground connections 2 and 6, condenser 5 anddetector I. The relay here shown and indicated in general by thereference numeral 2I, is also provided with an armature III and a pairof contacts I I and I2 which similarly function to close a circuitincluding the battery I5 and the primary winding of the transformer I3.In place of the energizing coil 8 of Fig. 1, however, there is hereshown a pair of coils 221 and 23 which are disposed on opposite sides ofthe armature ISL The armature I is of a suitable material such as asteel alloy, which is incapable of any permanent magnetization. Thecoils 22 and 23 are wound upon suitable cores given a permanentmagnetization by the horseshoe magnet 2li, although other means ofVmagnetizing the cores Vof the coils may be used. In the device shown inFig. 2 there is also shown a plurality of fixed condensers 25, 225 and271 which serve to bypass the armature It, and the contacts I I and IZto ground. These condensers are preferably included in the circuit toyreduce noise at the contacts II and I2 during the movement of thearmature I il. The circuit shown also includes an additional transformer28, having its primary connected to the secondary i8 of the firstmentioned transformer and the secondary of the transformer 2t isconnected to the voice coil I9.

The operation of the device shown in Fig. 2 is in general similar tothat shown in Fig. l. The armature Ii) is attracted successively toclose a circuit first through one of the contacts II and then throughcontact I2, depending on the values of the current through coils 22 and23. As eX- plained in connection with Fig. l, the current through theenergizing coils of the relay is a pulsating current of audio frequency.The rapid movement of the armature IEl is therefore of a correspondingfrequency and a similar current is set up in the primary I3.

The relay ZI is shown in greater detail in Figs. 4 to 6 inclusive.Referring to Fig. 4, it may be noted that the` contacts I I and I2 aremounted at the end of adjusting screws 2 and 3U which are in turncarried by suitable nuts 3i, 32, 33 and 34. The nuts are in turnsupported by clevis members 35 and 36, and each of the screws 29 and 30is provided with an adjusting head 31 and 38, respectively. The clevismembers 35 and 35, as Well as the remaining elements of the relay, aresuitably fastened to a base D. The armature IIB is fastened to asuitable support 39 by a screw It. Also carried on the screw is anadjusting spring 4I, rebent to contact the arma-ture I6. An adjustingscrew 42 is threaded through the support 39, and as shown can be movedinwardly and outwardly to move the armature toward one or the other ofthe coils 22 and 23 or the contacts II and I2. The contact points II andI2 are preferably of a non-oXidable conducting material such as silver,and the armature I@ is preferably provided with a similar non-oxidablecoating or insert opposite the contacts.

Referring to Fig. 8, there is illustrated a modication in which theantenna primary and secondary radio frequency coils, tuning condenserand rectifier are similar and havesimilar reference numerals to thoseshown in Fig. l. In place of the coil 8, a neon tube i3 is providedconnected in circuit with a transformerarrangement indicated in generalat de. rI'he transformer arrangement includes two coils #i5 and d, woundin opposed relationship upon respective legs il and d8 of a magneticcore, indicated in general by the reference numeral 553. One of the endsof each of the coils 45 and 45 is joined at 5t and the other ends of thecoil are connected through the xed capacities 5I and 52 to one side ofthe detector 'i and the neon tube 123. A variable condenser 53 isprovided which connects the joined end of the coils to ground. Woundabout both of the legs of the iron core, there is also provided a coilindicated by the reference numeral 5d. The coil 56 is positioned inseries with a variable resistance 55, a battery 5&5, and the primary ofa transformer 5l. The secondary of the transformer 5l is connected incircuit with the voice coil 58 of the speaker 59. As shown in Fig. 8,the magnetic core 4! is closed at each end.

The various elements constituting the circuit of Fig. 8 are so arrangedthat when a signal is received in the tuned circuit, currents are set upin the coils d5 and i5 which tend to saturate to a greater or lesserdegree the core MI, which is preferably made of an alloy requiring verylittle current for saturation. The degree of saturation of the iron corewill determine the current flow through the coil 53, and produce in thecoil 5 and primary of the transformer 51 a corresponding amplifiedcurrent of VVa similar frequency. The current through the primary of thetransformer 57 will of course be transformed into a correspondingalternating current at the secondary and pass through the voice coil 58for actuating the speaker.

The novel detector 'l of the present invention may be made in thefollowing manner:

100 grams of lead, which is desirably the lead of commerce and which maycontain the ordinary amount of impurities, is melted in a pot providedwith a cover. After the lead is melted to a fluid molten condition, thecover of the pot is removed, and there is added a chunk or mass ofselenium, the amount of selenium added being about ten (10) grams.Substantially immediately after the selenium is added, the cover isplaced on the vessel containing the molten lead and selenium, and thecontents of the vessel are allowed to solidify. The function of thecover on the vessel is to prevent the selenium from vaporizing. Insteadof using the means set forth, other means may be employed to prevent thevaporization of the selenium.

With the quantities above used, the time of solidication is usuallyabout five (5) minutes. It is recognized that the time of cooling of thematerial may be shorter or longer depending upon the initial temperatureand the quantity of the lead and the character of the pot in which thematerials are being treated.

Upon cooling, there is present in the treatment pot a composite masscomprising a central portion A, as shown in Figure 3, having a positioncorresponding to that where the selenium was dropped, said centralportion of the composite mass being black in color. This central massmay be termed a selenium-containing entity.

It is to be noted that surrounding the central f mass A, there is anintermediate zone or layer, also black in appearance, the black beingmore predominant adjacent the zone A and fading away until it approachesthe bottom layer C, which is a stratified layer of lead bright in color.

It is to be noted that the detector of the present invention is acomposite mass comprising a selenium-containing entity having inintimate Contact therewith a relatively better conducting medium, saidcomposite mass being capable of passing and demodulating a relativelyhigh amount of modulated high frequency alternating current.

In the illustration herein set forth, a lead and/or a lead-containingentity functions in combination with the selenium-containing entity toform a detector capable of passing and demodulating a relatively highamount of modulated high frequency alternating current. However, anyother conducting medium may be used which will function in combinationwith the selenium-containing entity to pass and demodulate a relativelyhigh amount of modulated high frequency alternating current. In otherWords, While there is set forth one suitable conducting medium whichfunctions as a relatively better conducting medium than theseleniumcontaining entity, it will become apparent to those skilled inthe art, upon the disclosure of the present invention, what equivalentsmay be used, and it is desired to be protected both specifically andbroadly,

It has been stated that the detector of the present invention is capableof passing and dernodulating a relatively high amount of modulated highfrequency alternating current. By this is meant that the detector of thepresent invention is capable of passing a current of approximately 1 to2 milliamperes, whereas the best prior art detectors for currents of themodulated radio frequency type operating without any auxiliaryexcitation are only capable of passing 0.05 milliampere, which haseifectually militated against their use where further amplification isdesired.

It has been stated that the detector forming a partr of the presentinvention comprises a selenium-containing entity having in intimatecontact therewith a relatively better conducting medium functioning asset forth. By the expression in intimate contact therewith there ismeant the Contact that is eiected by adding a pellet of selenium tomolten lead, which is then in situ solidified. By this addition and insitu solidii'lcation, there is apparently produced a distribution orinfiltration of a portion of selenium into the surrounding lead layer,and some distribution of the lead into the selenium mass or entityhereinbefore mentioned, since this selenium mass or entity is thencapable, to some extent, of conducting current. It may be pointed outfurther that apparently some of the lead is incorporated in the seleniummass because selenium itself does not conduct current in any way. Aseriesof tests have been made on the rectifier of the present invention,using a forty-five (45) volt dry cell battery and an ordinary type of D.C. voltmeter in circuit therewith. One of the terminals of the batterywas connected during all of these tests to the layer designated as C inFigure 6. The other terminal of the circuit leading through thevoltmeter to the battery was then connected alternately to layer C,layer B and layer A. There was apparently no voltage drop through thelayer C, that is, when both yterminals of the circuit were connected tolayer C. The voltmeter reading when one of the terminals was connectedto the layer B was approximately thirty-five (35) volts, and the voltagereading when one terminal was connected to layer A was approximatelynineteen 1.9) volts. It was thus shown that the layer C had theconductivity and was apparently composed of pure lead; that the layer Bwas only slightly less in conductivity than pure lead, and must,therefore, have contained a considerable portion of lead and arelatively small proportion of selenium; that the layer A was a poorconductor for ordinary D. C. currents and must, therelore, havecontained a comparatively large and/or predominant proportion ofselenium.

Other tests have also been made to establish the rectiiyingcharacteristics of the combined mass, and it has been found that inorder to produce the detector of the present invention, all three ofthese zones or layers should desirably be present. When the layer C ofpure lead was removed and contact made directly to the layer B, norectification took place, nor did any current pass when these two layerswere put in circuit with an ordinary source of radio frequency waves.The same phenomena occurred when it was attempted to eliminate the layerB or the layer A. When layer A was eliminated and pure seleniumsubstituted therefor, there were no results, as the selenium did notpass any current whatsoever.

It has been stated that the detector is produced by adding 10 grains ofsolid selenium to 100 grams of molten lead. These proportions can bevaried. If a greater quantity than 10 grams of selenium is added to 100grams of molten lead, the device will function as a detector, but noincrease in efficiency will be observed, that is, the detector Willstill be capable of passing 1 to 2 milliamperes and 10 to 15 volts froman antenna as before set forth, and no more.

It may be pointed out that if the proportion of selenium is increased tosuch an extent that the conductivity of the entire mass is cut down,that is, if the amount of selenium added greatly exceeds the amount oflead, then no rectication at all will take place. If less than ten gramsoi selenium are added to the one hundred (105) grams of lead, the amountof current passed, or the amount of current rectified will besubstantially decreased.

It is desired to state that on the upper surface of the composite mass,made in accordance with the method above set forth, there appears smallred spots, which are probably selenium oxide. Naturally, some oxidationdoes occur.

It is not desired to be limited by any theory as to the reaction betweenthe selenium and the lead components. However, it is likely that thecenter mass A, which is selenium, has reacted at least to some extent,to produce a lead selenium combination which is distributed in theselenium, or that there is a solid solution of the lead into theselenium which enables the selenium to function as a conductor ofcurrent, as hereinbefore set forth, it being Well known in the art thatselenium itself is a non-conductor. On the other hand, it may well bethat no solution of the selenium in the lead occurs or vice versa, and

that the mass A is in reality a mass of selenium which has, by thetreatment herein set forth, been modiiied so as to cause it to functionas a conductor of current.

` The detector when produced in accordance with the process hereinbeforeset forth is preferably connected in circuit and the radio frequencyWaves are allowed to pass therethrough for a considerable period oftime. It has been found that the ability of the detector to rectify andpass currents is improved during the first several hours of operationuntil it reaches a maximum operating efciency. Once the maximumoperating efficiency is established, however, it appears to remain at aconstant indefinitely. While the novel detector of the present inventionhas been disclosed as operating in connection with radio circuits, itmay be used for other similar purposes; for example, where modulatedhigh frequency currents are being transmitted over a wire. It can alsobe used for detection purposes in radio therapeuty or diathermy. and itcan also be used in the production of delicate measuring instruments. Itis responsive not only to the ordinary broadcast band of frequencies,but also to the short Waves and ultra short waves known in the art. Inother Words, the present detector will rectify any frequency above theaudible range.

It is desired to point out that the electrical values of the variousparts used in the assembly of the radio according to the presentinvention are capable of considerable variation and change, is known inthe art. However, it has been found that it is preferable that the coils22 and 23 as used have a comparatively high resistance. By way ofexample, this resistance may be similar to the coils found in anordinary pair of head phones.

The present application is continuation in part of my prior applicationSerial No. 199,010, led March 30, 1938.

Iclaim:

1. An amplier for high frequency currents comprising av plurality ofconducting members substantially xedly separated by an insulatingmedium, means to complete a circuit alternately through said membersincluding a local current source, and a vibratory means, means tooperate said vibratory means in synchronism With the frequencies to beamplified, and responsive means in circuit with said conducting members,said vibratory means, and said local current source, the current in saidcircuit being adapted to impress on said responsive means a resultantcurrent substantially corresponding in frequency and Wave form to theoriginal current supplied to the amplifier.

2. A system for the detection and amplification of modulated radiosignals comprising a circuit for receiving said signals, a detector insaid circuit and an amplifier comprising a plurality of conductingmembers substantially xedly separated by an insulating medium, means tocomplete a circuit alternately through said members including a localcurrent source, and a vibratory means, means to operate said vibratorymeans in synchronism with the frequency to be amplified and responsivemeans in circuit with said conducting members, said vibratory means, andsaid local current source, the current in said circuit being adapted toimpress on said responsive means a resultant current substantiallycorresponding in frequency and Wave form to the detected current in theoriginal receiving circuit.

3. A system for the detection and amplification of modulated radiosignals, comprising a circuit for receiving said signals, a detector insaid circuit comprising the reaction product of a pellet of selenium andmolten lead, said pellet substantially retaining its pellet form, an-ampliiier in said circuit comprising a plurality of conducting memberssubstantially Xedly separated by an insulating medium, means to completea circuit alternately through said members including a local currentsource, and a vibratory means, means to operate said vibratory means insynchronism with -the frequency to be amplified and responsive means incircuit with said conducting members, said vibratory means, and saidlocal current source, the current in said circuit being adapted toimpress on said responsive means a resultant current substantiallycorresponding in frequency and Wave form to the detected current in theorlginal receiving circuit.

4. An amplifier for high frequency currents comprising a plurality ofconducting members substantially lxedly separated by an insulatingmedium, means to complete a circuit alternately through said membersincluding a local current source and a vibratory armature, a coil incircuit With the current to be amplified Iand adapted. to vibrate saidarmature in synchronism with the current frequency, and responsive meansin circuit With said conducting members, said vibratory means, and saidlocal current source, the current in said circuit being adapted toimpress on said responsive means, a resultant current substantiallycorresponding in frequency and Wave :form to the original currentsupplied to the ampliiier.

5. A system for the detection and amplication of modulated radio signalscomprising a tuned circuit for receiving said signals, a detector insaid circuit, a relay comprising an energizing coil connected in saidcircuit after said detector and an armature, a local source of currentconnected to said relay armature, a plurality of conducting memberssubstantially fnredly separated by an insulating medium and adapted tobe alternately connected to said local source of current by saidarmature, means to connect portions of a transformer primary to saidconducting members, means to connect each of said portions to said localsource of current, said connecting means being so arranged thatalternate connection of said conducting members and the source ofcurrent by the armature will establish a circuit from said source ofcurrent alternately through each primary portion in opposite directionsso as to produce in said primary a full wave pulsating D. C. current anda transformer secondary magnetically coupled to said primary.

6. A system for the detection and amplification of modulated radiosignals comprising a circuit for receiving said signals, a detector insaid circuit, a relay comprising an energizing coil connected in saidcircuit after said detector and an armature, a local source of currentconnected to said relay armature, a plurality of contacts adapted to bealternately connected to said local source of current by said armature,means to connect portions of a transformer primary to said contacts andmeans to connect each of said portions to said local source of current,said connecting means being so arranged that alternate connection ofsaid contacts and the source of current by the armature will establish acircuit from said source of current alternately through each primaryportion in opposite directions to thereby produce in said primary a fullwave pulsating DC current.

'7. A system for the detection and amplification of modulated radiosignals comprising a tuned circuit for receiving said signals, adetector in said circuit, a relay comprising an energizing coilconnected in said circuit after said detector and an armature, a localsource of current connected to said relay armature, a plurality ofcontacts adapted to be alternately connected to said local source ofcurrent by said armature, a transformer having a primary windingincluding a center tap and two end taps, means to connect the end tapsIof said primary to said contacts and means to connect the center tap ofsaid primary to the local source of current so that the alternateconnection of said contacts and the source of current by the armaturewill establish a circuit from said source of current alternately througheach portion of said transformer primary between said center tap andsaid end taps to produce a current lioW through each of said portions inopposite directions to thereby produce in said primary a full Wavepulsating DC current.

8. A system for the detection and amplification of radio signalscomprising means to receive said radio signals, a detector comprisingthe reaction product of a pellet of selenium and molten lead said pelletsubstantially retaining its pellet form, and means operated by thedemodulated signals for producing from a local source a correspondingsignal of any desired intensity.

9. A combination selenium-lead rectifier comprising the reaction productof a pellet of selenium andmolten lead, said pellet substantiallyretaining its pellet form.

10. A selenium rectifier for demodulating high frequency currentscomprising the reaction product of a pellet of selenium and a moltenconducting metallic material having the general characteristics of lead,said rectifier exhibiting on fracture three zones of material blendinginto one another, one zone resembling the original form of .the pelletand having a substantially high resistance, another zone having asubstantially low resistance, and exhibiting the characteristics of theaforesaid metallic material, and a third zone having a resistanceintermediate the other two, separating the first two mentioned zones.

11. A combination selenium-lead rectifier comprising the reactionproduct of a pellet of selenium and molten lead, exhibiting on fracturethree zones of material blending into one another, one zone resemblingthe original form of said pellet and having a substantially highresistance, another zone having a substantially low resistance, andexhibiting the characteristics of the lead, and a third zone having aresistance intermediate to the other two, separating the tWo firstmentioned zones.

12. An amplifier for high frequency currents comprising a plurality oi'conducting members substantially xedly separated by an insulatingmedium, means to complete a circuit alternately through said membersincluding a local current source and a vibratory means, a plurality ofopposed operating means adapted to move said vibratory means insynchronism with the frequency to be amplified, and responsive means incircuit with said conducting means, said Vibratory means, and said localcurrent source, the current in said circuit being adapted to impress onsaid responsive means a resultant current substantially corresponding infrequency and wave form to the original current supplied to theamplifer.

13. An amplifier for high frequency currents comprising a plurality ofconducting members substantially xedly separated by an insulatingmedium, means to complete a circuit alternately through said membersincluding a local current source and a vibratory armature, a pluralityof coils in circuit with the current to be amplified, said coils beingpositioned in opposed relation relative to said armature to thereby movesaid armature in synchronisrn with the current frequency and responsivemeans in circuit with said conducting members, said vibratory means, andsaid local current source, the current in said circuit being adapted toimpress on said responsive means, a resultant current substantiallycorresponding in frequency and Wave form to the original currentsupplied to the amplier.

14. An amplifier for high frequency currents comprising a plurality ofconducting members substantially xedly separated by an insulatingmedium, means to complete a circuit alternately through said membersincluding a local current source and a vibratory armature, a pair ofcoils in circuit with the current to be amplified, each of said coilsbeing positioned on one side of said armature and adapted when energizedto move the same, a magnetic core disposed Within each coil, each ofsaid cores constituting magnetic poles of diverse polarity andresponsive means in circuit with said conducting members, said vibratorymeans, and said local current source, the current in said circuit beingadapted to impress on said responsive means a resultant current substantially corresponding in frequency and wave form to the original currentsupplied to the amplifier.

15. A system for detection and amplification of modulated radio signalscomprising a tuned circuit for receiving said signals, a detector insaid circuit, a relay comprising a pair of coils connected in circuitafter said detector and an armature, a local source of current connectedto said relay armature, a plurality of contacts adapted to bealternately connected to said local source of current by said armature,means to connect portions of a transformer primary to said contacts andmeans to connect each of said portions to said local source of current,said connecting means being so arranged that alternate connection ofsaid contacts and the source of current by the armature will establish acircuit from said source of current alternately through each primaryportion in opposite directions to thereby produce in said primary a fullWave pulsating D. C. current.

16. A system for detection and amplication of modulated radio signalscomprising a tuned circuit for receiving said signals, a detector insaid circuit, a relay comprising a pair of energizing coils connected insaid circuit after said detector and positioned on each side of anarmature, said coils being adapted when energized to move the iarmature, a magnetic core in each coil, each core constituting amagnetic pole of diverse polarity, a local source of current connectedto said-relayA armature, a plurality of contacts adapted to bealternately connected to vsaid local source of current by said armature,a transformer having a primary Winding lincluding a center tap and twoend taps, means to connect the end taps or said primary to said contactsandv means to connect the center tap of the primary to the local sourceof current so that the alternate connection of said contacts and thesource of current by the armature Will establish a circuit from saidsource of current alternately through each portion of said transformerprimary between said center tap and said end taps to produce a currentow through each of said portions in opposite directions to therebyproduce in said primary a full Wave puisating D. C. current.

J. GUZMAN TOVAR.

